javascript - Find html element nearest to position (relative or absolute)

Question

Given absolute or relative position (top & left) is there any way to get the nearest html element to these co-ordinates?

Or alternately, is there any way to craft a selector (or use some jQuery construct) to enumerate elements and then find which is closes to the provided co-ordinates? Assume that the set of elements is small and finite.

Answer 1

I've built a jQuery method that returns closest element to offset, within the collection:

jQuery.fn.closestToOffset = function(offset) {
    var el = null,
        elOffset,
        x = offset.left,
        y = offset.top,
        distance,
        dx,
        dy,
        minDistance;
    this.each(function() {
        var $t = $(this);
        elOffset = $t.offset();
        right = elOffset.left + $t.width();
        bottom = elOffset.top + $t.height();

        if (
            x >= elOffset.left &&
            x <= right &&
            y >= elOffset.top &&
            y <= bottom
        ) {
            el = $t;
            return false;
        }

        var offsets = [
            [elOffset.left, elOffset.top],
            [right, elOffset.top],
            [elOffset.left, bottom],
            [right, bottom],
        ];
        for (var off in offsets) {
            dx = offsets[off][0] - x;
            dy = offsets[off][1] - y;
            distance = Math.sqrt(dx * dx + dy * dy);
            if (minDistance === undefined || distance < minDistance) {
                minDistance = distance;
                el = $t;
            }
        }
    });
    return el;
};

Notes:

1. If the offset is inside one of the elements, it will be returned.
2. I'm looping through four offsets, because this gives the best accuracy.

Use it like this:

$('div.myCollection').closestToOffset({left: 5, top: 5});